A variable valve mechanism 90 of Patent Literature 1 (Related Art Document 1) shown in FIG. 8, a variable valve mechanism 90′ of Patent Literature 2 (Related Art Document 2) shown in FIG. 9, variable valve mechanisms of Patent Literature 3 and Patent Literature 4 (Related Art Documents 3 and 4), not shown, etc. are known as valve mechanisms having a halt function to halt driving of a valve and a variable function such as an working-angle variable function to vary the working angle, etc.
These variable valve mechanisms 90, 90′ are configured to include: a rotary cam 91 that rotates according to rotation of an internal combustion engine; an output arm 92 that is swingably provided and that drives a valve 7 when swinging; an input arm 93 that is provided so as to be swingable relative to the output arm 92, and that includes an input roller 98 contacting the rotary cam 91; and a switching device 94 that switches between a coupled state where the output arm 92 is coupled to the input arm 93 so as not to allow the input arm 93 to swing relative to the output arm 92 and a non-coupled state where the coupling between the output arm 92 and the input arm 93 is released so as to allow the input arm 93 to swing relative to the output arm 92. The variable valve mechanisms 90, 90′ change the drive state of the valve 7 by the switching operation.